Hulet C V, Ercanbrack S K, Knight A D
J Anim Sci. 1984 Jan;58(1):15-24. doi: 10.2527/jas1984.58115x.
Development of the Polypay breed was undertaken to combine into a composite breed the potential for greatly increased reproductive capacity along with desirable growth rate and carcass quality. Four breeds were selected for the foundation of the new breed--the Rambouillet and the Targhee for hardiness, large body size, long breeding season, herding instinct and fleece characteristics; the Dorset for carcass quality, milking ability and long breeding season and the Finnsheep for early puberty, early postpartum fertility and high lambing rate. Dorset X Targhee and Finnsheep X Rambouillet matings were first made in 1968, and reciprocal Dorset-Targhee X Finn-Rambouillet matings were initiated in 1969. Beginning in 1970, the respective two-breed crosses and the four-breed cross (Polypay) were each mated inter se and selected, along with straightbred Rambouillets and Targhees, for lamb production when given two opportunities to lamb/year. Initial comparisons among straightbreds and inter se mated groups showed few important differences in meat-type body conformation, body condition or growth rate, but superior annual reproductive performance by Polypays. Fertility of Polypays at 1 yr of age was high and comparable to that of the Finn-Rambouillets. Response of Polypays to twice-a-year lambing was superior to responses of Rambouillets. Targhees, Dorset-Targhees or Finn-Rambouillets. The 1974 to 1975 annual production of young Polypays was about 13% more lambs weaned than from Finn-Rambouillets and 18% more weight of lamb weaned than from Dorset-Targhees, the best of the other groups for these traits. The current (1979 to 1981) reproductive performance of Polypay ewes selected for high once-a-year lambing rate under typical range management conditions is very competitive with that of 1/2 Finn crossbreds. Annual production of mature Polypays on the twice-a-year lambing schedule was 1.78 lambs weaned and 58.6 kg of lamb weaned/ewe put into fall breeding.
波利佩羊品种的培育旨在将大幅提高繁殖能力的潜力与理想的生长速度和胴体品质结合起来，形成一个复合品种。为培育这个新品种选择了四个品种——兰布耶羊和塔吉羊，因其耐寒性、体型大、繁殖季节长、放牧本能和羊毛特性；多塞特羊因其胴体品质、泌乳能力和繁殖季节长；芬兰羊因其早熟、产后早期繁殖力和高产羔率。多塞特羊×塔吉羊和芬兰羊×兰布耶羊的杂交首次在1968年进行，多塞特 - 塔吉羊×芬兰 - 兰布耶羊的反复杂交在1969年开始。从1970年起，各自的两品种杂交后代和四品种杂交后代（波利佩羊）相互交配并进行选择，同时选择纯种兰布耶羊和塔吉羊，在每年有两次产羔机会的情况下进行产羔性能的选育。纯种羊和相互交配组之间的初步比较表明，在肉用体型、体况或生长速度方面几乎没有重要差异，但波利佩羊的年繁殖性能更优。波利佩羊1岁时的繁殖力很高，与芬兰 - 兰布耶羊相当。波利佩羊对一年产羔两次的反应优于兰布耶羊、塔吉羊、多塞特 - 塔吉羊或芬兰 - 兰布耶羊。1974年至1975年，波利佩羊幼羊的年产量比芬兰 - 兰布耶羊断奶羔羊数多约13%，断奶羔羊体重比多塞特 - 塔吉羊（在这些性状上表现最佳的其他组）多18%。在典型的牧场管理条件下，为高一年产羔率选育的波利佩母羊目前（1979年至1981年）的繁殖性能与1/2芬兰杂交羊的繁殖性能非常有竞争力。按一年产羔两次的计划，成年波利佩羊的年产量为每只进入秋季配种的母羊断奶1.78只羔羊，断奶羔羊体重58.6千克。
